In this study,a numerical flow model of the fission products(FPs)in the primary loop system of a molten salt reactor(MSR)was established and solved using Mathematica 7.0.The simulation results were compared with those...In this study,a numerical flow model of the fission products(FPs)in the primary loop system of a molten salt reactor(MSR)was established and solved using Mathematica 7.0.The simulation results were compared with those of the ORIGEN-S program in the static burnup mode,and the deviation was found to be less than 10%,which indicates that the results are in good agreement.Furthermore,the FPs distribution in the primary loop system under normal operating conditions of the 2 MW MSR was quantitatively analyzed.In addition,the distribution phenomenon of the FPs under different flow rate conditions was studied.At the end of life,the FPs activity in the core region(including active region,and upper and lower plenum regions)accounted for 77.3%,and that in the hot leg #1,main pump,hot leg #2,heat exchanger,and cold leg region accounted for 1.2%,16.15%,0.99%,2.5%,and 1.9%,respectively,of the total FPs in the primary loop under normal operating conditions.The proportion of FPs in the core decreased with the increase in flow rate in the range of 2.24-22,400 cm^3 s^-1.The established analytical method and conclusions of this study can provide an important basis for radiation safety design of the primary loop,radioactive source management design,thermal-hydraulic safety analysis,and radiochemical analysis of FPs of 2 MW MSRs.展开更多
This paper presents a neutronics design of a 10 MW ordered-pebble-bed fluoride-salt-cooled high-temperature experimental reactor. Through delicate layout, a core with ordered arranged pebble bed can be formed,which ca...This paper presents a neutronics design of a 10 MW ordered-pebble-bed fluoride-salt-cooled high-temperature experimental reactor. Through delicate layout, a core with ordered arranged pebble bed can be formed,which can keep core stability and meet the space requirements for thermal hydraulics and neutronics measurements.Overall, objectives of the core include inherent safety and sufficient excess reactivity providing 120 effective full power days for experiments. Considering the requirements above, the reactive control system is designed to consist of 16 control rods distributed in the graphite reflector. Combining the large control rods worth about 18000–20000 pcm, molten salt drain supplementary means(-6980 to -3651 pcm) and negative temperature coefficient(-6.32 to -3.80 pcm/K) feedback of the whole core, the reactor can realize sufficient shutdown margin and safety under steady state. Besides, some main physical properties, such as reactivity control, neutron spectrum and flux, power density distribution, and reactivity coefficient,have been calculated and analyzed in this study. In addition, some special problems in molten salt coolant are also considered, including ~6Li depletion and tritium production.展开更多
The neutronic properties of molten salt reactors(MSRs)differ from those of traditional solid fuel reactors owing to their nuclear fuel particularity.Based on the Monte-Carlo N particle transport code,the effects of th...The neutronic properties of molten salt reactors(MSRs)differ from those of traditional solid fuel reactors owing to their nuclear fuel particularity.Based on the Monte-Carlo N particle transport code,the effects of the size and shape of the fuel salt channel on the neutron physics of an MSR cell are investigated systematically in this study.The results show that the infinite multiplication factor(k?)first increases and then decreases with the change in the graphite cell size under certain fuel volume fraction(FVF)conditions.For the same FVF and average chord length,when the average chord length is relatively small,the k?values for different fuel salt channel shapes agree well.When the average chord length is relatively large,the k?values for different fuel salt channel shapes differ significantly.In addition,some examples of practical applications of this study are presented,including cell selection for the core and thermal expansion displacement analysis of the cell.展开更多
The production of radionuclides(90)^Sr and(131)^I in molten salt reactors is an attractive option to address the global shortage of radionuclides.This study evaluated the production characteristics of(90)^Sr and(131)^...The production of radionuclides(90)^Sr and(131)^I in molten salt reactors is an attractive option to address the global shortage of radionuclides.This study evaluated the production characteristics of(90)^Sr and(131)^I in a modular molten salt reactor,such as equilibrium time,yield,and cooling time of isotopic impurities.The fuel burn-up of a small modular molten salt reactor was analyzed by the Triton module of the scale program,and the variation in the fission yields of the two nuclides and their precursors with burn-up time.The yield of(131)^I and~(131)Te has been increasing during the lifetime.131 I has an equilibrium time of about 40 days,a saturation activity of about 40,300 TBq,and while~(131)Te takes 250 min to reach equilibrium,the equilibrium activity was about 38,000 TBq.The yields of90 Sr and~(90)Kr decreased gradually,the equilibrium time of90 Kr was short,and(90)^Sr could not reach equilibrium.Based on the experimental data of molten salt reactor experiment,the amount of nuclide migration to the tail gas and the corresponding cooling time of the isotope impurities under different extraction methods were estimated.Using the HF-H_2 bubbling method,3.49×10^(5)TBq of(131)^I can be extracted from molten salt every year,and after13 days of cooling,the impurity content meets the medical requirements.Using the electric field method,1296 TBq of(131)^I can be extracted from the off-gas system(its cooling time is 11 days)and 109 TBq of(90)^Sr.The yields per unit power for(131)^I and(90)^Sr is approximately 1350 TBq/MW and 530 TBq/MW,respectively,which shows that molten salt reactors have a high economic value.展开更多
基金supported by the Chinese Academy of Sciences TMSR Strategic Pioneer Science and Technology Project(No.XDA02010000)The Frontier Science Key Program of Chinese Academy of Sciences(No.QYZDY-SSW-JSC016)
文摘In this study,a numerical flow model of the fission products(FPs)in the primary loop system of a molten salt reactor(MSR)was established and solved using Mathematica 7.0.The simulation results were compared with those of the ORIGEN-S program in the static burnup mode,and the deviation was found to be less than 10%,which indicates that the results are in good agreement.Furthermore,the FPs distribution in the primary loop system under normal operating conditions of the 2 MW MSR was quantitatively analyzed.In addition,the distribution phenomenon of the FPs under different flow rate conditions was studied.At the end of life,the FPs activity in the core region(including active region,and upper and lower plenum regions)accounted for 77.3%,and that in the hot leg #1,main pump,hot leg #2,heat exchanger,and cold leg region accounted for 1.2%,16.15%,0.99%,2.5%,and 1.9%,respectively,of the total FPs in the primary loop under normal operating conditions.The proportion of FPs in the core decreased with the increase in flow rate in the range of 2.24-22,400 cm^3 s^-1.The established analytical method and conclusions of this study can provide an important basis for radiation safety design of the primary loop,radioactive source management design,thermal-hydraulic safety analysis,and radiochemical analysis of FPs of 2 MW MSRs.
基金supported by the Chinese Academy of Sciences TMSR Strategic Pioneer Science and Technology Project(No.XDA02010000)Thorium uranium fuel cycle characteristics and key problem research Project(No.QYZDY-SSW-JSC016)
文摘This paper presents a neutronics design of a 10 MW ordered-pebble-bed fluoride-salt-cooled high-temperature experimental reactor. Through delicate layout, a core with ordered arranged pebble bed can be formed,which can keep core stability and meet the space requirements for thermal hydraulics and neutronics measurements.Overall, objectives of the core include inherent safety and sufficient excess reactivity providing 120 effective full power days for experiments. Considering the requirements above, the reactive control system is designed to consist of 16 control rods distributed in the graphite reflector. Combining the large control rods worth about 18000–20000 pcm, molten salt drain supplementary means(-6980 to -3651 pcm) and negative temperature coefficient(-6.32 to -3.80 pcm/K) feedback of the whole core, the reactor can realize sufficient shutdown margin and safety under steady state. Besides, some main physical properties, such as reactivity control, neutron spectrum and flux, power density distribution, and reactivity coefficient,have been calculated and analyzed in this study. In addition, some special problems in molten salt coolant are also considered, including ~6Li depletion and tritium production.
基金This work was supported by the Chinese TMSR Strategic Pioneer Science and Technology Project(No.XDA02010000)the Frontier Science Key Program of Chinese Academy of Sciences(No.QYZDYSSW-JSC016)the Shanghai Sailing Program(No.Y931021031).
文摘The neutronic properties of molten salt reactors(MSRs)differ from those of traditional solid fuel reactors owing to their nuclear fuel particularity.Based on the Monte-Carlo N particle transport code,the effects of the size and shape of the fuel salt channel on the neutron physics of an MSR cell are investigated systematically in this study.The results show that the infinite multiplication factor(k?)first increases and then decreases with the change in the graphite cell size under certain fuel volume fraction(FVF)conditions.For the same FVF and average chord length,when the average chord length is relatively small,the k?values for different fuel salt channel shapes agree well.When the average chord length is relatively large,the k?values for different fuel salt channel shapes differ significantly.In addition,some examples of practical applications of this study are presented,including cell selection for the core and thermal expansion displacement analysis of the cell.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA02010000)Thorium Uranium Fuel Cycle Characteristics and Key Problem Research Project(No.QYZDY-SSW-JSC016)Shanghai Natural Science Foundation(No.19ZR1468000)。
文摘The production of radionuclides(90)^Sr and(131)^I in molten salt reactors is an attractive option to address the global shortage of radionuclides.This study evaluated the production characteristics of(90)^Sr and(131)^I in a modular molten salt reactor,such as equilibrium time,yield,and cooling time of isotopic impurities.The fuel burn-up of a small modular molten salt reactor was analyzed by the Triton module of the scale program,and the variation in the fission yields of the two nuclides and their precursors with burn-up time.The yield of(131)^I and~(131)Te has been increasing during the lifetime.131 I has an equilibrium time of about 40 days,a saturation activity of about 40,300 TBq,and while~(131)Te takes 250 min to reach equilibrium,the equilibrium activity was about 38,000 TBq.The yields of90 Sr and~(90)Kr decreased gradually,the equilibrium time of90 Kr was short,and(90)^Sr could not reach equilibrium.Based on the experimental data of molten salt reactor experiment,the amount of nuclide migration to the tail gas and the corresponding cooling time of the isotope impurities under different extraction methods were estimated.Using the HF-H_2 bubbling method,3.49×10^(5)TBq of(131)^I can be extracted from molten salt every year,and after13 days of cooling,the impurity content meets the medical requirements.Using the electric field method,1296 TBq of(131)^I can be extracted from the off-gas system(its cooling time is 11 days)and 109 TBq of(90)^Sr.The yields per unit power for(131)^I and(90)^Sr is approximately 1350 TBq/MW and 530 TBq/MW,respectively,which shows that molten salt reactors have a high economic value.
